Secondary battery boost circuit

• US 5,835,366 A
• Filed: 06/24/1997
• Issued: 11/10/1998
• Est. Priority Date: 06/24/1997
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Telxon Corporation (Zebra Technologies Corporation)
• Inventors: Pleso, Mark F., Leppo, Lee E.
• Primary Examiner(s): Hecker, Stuart N.
• Application Number:
  US08/881,773
• Time in Patent Office: 504 Days
• Field of Search: 323/21, 323/222, 363/59, 307/64, 307/66
• US Class Current: 363/59
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

A secondary battery boost system which includes a primary power supply for a computing device, and a secondary power supply for the computing device. The boost system also includes a boost circuit operative to increase the power output of the secondary power supply applied to the computing device. Upon the output of the primary power supply falling below a level suitable for properly powering the computing device, the boost circuit feeds the computing device power from the secondary power supply. The boost circuit also boosts the power output of the secondary power supply so that the secondary power supply can be smaller and more light weight.

Claims

1. A secondary battery boost system, comprising:

a primary battery, the primary battery operative as a primary portable power supply for a computing device;

a secondary battery, the secondary battery operative as a backup portable power supply for the computing device; and

a boost circuit operative to increase the power output of the secondary battery applied to the computing device.

2. The secondary battery boost system of claim 1, wherein the boost circuit is adapted to provide power to the computing device from the secondary battery when a voltage of the primary battery falls below a predetermined threshold.

3. The secondary battery boost system of claim 2, further including a low voltage detection circuit for monitoring the voltage level of the primary battery.

4. The secondary battery boost system of claim 3, wherein the secondary battery supplies power to the computing device in order to sustain an advanced power management protocol when the power output of the primary battery falls below a predetermined threshold.

5. The secondary battery boost system of claim 4, wherein the boost circuit increases the power output of the secondary battery for a time period sufficient to complete the advanced power management protocol.

6. The secondary battery boost system of claim 1, wherein the computing device is a wireless mobile terminal.

7. A method for facilitating power shutdown protocol of a computing device, comprising the steps of:

using a first cell as a primary portable power supply for the computing device;

using a secondary cell as a backup portable power supply for the computing device; and

using a boost circuit to increase the power of the secondary cell applied to the computing device;

wherein the secondary cell supplies power to the computing device upon a voltage of the first cell dropping below a predetermined value.

8. The method for facilitating power shutdown protocol of a computing device of claim 7, wherein the step of the boost circuit increasing the voltage of the secondary cell applied to the computing device includes the step of the boost circuit providing power to the computing device from the secondary cell when a voltage of the primary cell falls below a predetermined threshold.

9. The method for facilitating power shutdown protocol of a computing device of claim 8, further including the step of using a low voltage detection circuit to monitor the voltage level of the primary cell.

10. The method for facilitating power shutdown protocol of a computing device of claim 7, further including the step of coupling the primary cell and the secondary cell to the boost circuit via a wired OR connection.

11. The method for facilitating power shutdown protocol of a computing device of claim 7, further including the step of using the secondary cell to supply power to the computing device in order to sustain an advanced power management protocol.

12. The method for facilitating power shutdown protocol of a computing device of claim 7, further including the step of using the boost circuit to increase the voltage output of the secondary cell for a time period sufficient to complete the advanced power management protocol.

13. A portable computing device, comprising:

a housing;

a first battery supported by the housing, the first battery operative to supply power via a power supply to the portable computing device;

a battery boost circuit disposed within the housing;

a secondary battery coupled to the battery boost circuit, the secondary battery operative to supply power via the power supply to the portable computing device upon a voltage of the first battery falling below a predetermined value;

wherein the battery boost circuit increases a power output of the secondary battery and provides the portable computing device with power from the secondary battery upon the voltage of the first battery falling below the predetermined value.

14. The portable computing device of claim 13, wherein the boost circuit is adapted to provide power to the portable computing device from the secondary battery when a power output of the primary battery falls below a predetermined threshold.

15. The portable computing device of claim 14, further including a low voltage detection circuit for monitoring the voltage level of the primary battery.

16. The portable computing device of claim 14, wherein the secondary battery supplies power to the computing device in order to sustain an advanced power management protocol when the power output of the primary battery falls below the predetermined threshold.

17. The portable computing device of claim 13, wherein the first battery and the secondary battery are coupled together via a wired OR connection.

18. The portable computing device of claim 13, wherein the portable computing device is a wireless mobile terminal.

19. The portable computing device of claim 13, wherein the portable computing device is a laptop computer.

20. A method of providing power to a computing device, comprising the steps of:

providing power to the computing device via a primary power source;

determining when an output power associated with the primary power source is below a threshold power level;

sensing the primary power source to determine if the output power associated with the primary power source falls below a predetermined power level;

providing power to the computing device via a secondary power source when the output power associated with the primary power source is determined to be below the threshold power level, the secondary power source providing power through a power boost circuit; and

triggering an advanced power management shutdown protocol upon determining that the output power is below the predetermined power level.

21. The method of claim 20, wherein the primary power source and the secondary power source are coupled together via a wired OR connection.

22. The method of claim 21, wherein the predetermined power level is greater then the threshold power level.

23. The method of claim 22, wherein the step of triggering an advanced power management shutdown protocol upon determining that the output power is below the predetermined power level, includes the step of using a low voltage detection circuit to monitor the voltage level of the primary power source.

24. The method of claim 23, wherein the computing device is a portable computing device capable of wireless communication.